There is an increasing usage of welding robots in the welding industry. Arc welding robotics systems consist of welding power source, wire feeder, robot controller, manipulator and welding torch. The welding torch is a key component of such systems. The torch delivers the welding power necessary to produce a fusion joint. The front-end components of the torch are exposed to harsh conditions near the arc region. The other components are exposed to mechanical strain and other environmental conditions. Failure of one or more components of a welding torch usually translate into a loss of weld quality which brings the automatic cell to a halt until the failed component(s) is(are) replaced. Normally, at this point, faulty welds must be repaired or the part must be scrapped which adds to the cost of lost productivity.
Monitoring devices capable of detecting faults before or right after they occur are highly desirable. Currently, there is limited preventive or diagnostic sensing of the process in robotic welding operations. Process soundness is typically determined by monitoring welding current and arc voltage and flagging alarms anytime their actual values fall outside predetermined thresholds. This is done by weld controllers using current and voltage signals from the welding power source. Arc welding is a complex process and threshold monitoring is not sufficient for full diagnostics of the process. It is desirable to produce a gas metal arc welding (GMAW) torch that integrates a series of sensing capabilities for intelligent complete diagnostics of the welding process in real time.